More than one in four American adults have left the faith in which they were brought up. So says exhaustive research from the Pew Forum on Religion and Public Life, based on interviews with 35,000 Americans aged 18 and up.

The survey also found that Protestantism will soon lose its status as the majority religion. It can only barely claim it now. Only 51% of religious Americans now declare they are members of one of the Protestant denominations, a significant drop from the 60% range 20 years ago.

The new Protestant world looks like this: A little more than 1 in 4 Protestants belongs to an evangelical church. Less than 1 in 5 belongs to a mainline Protestant Church. In mainline Protestant churches, half are age 50 and older.

The new Catholic world looks like this: Of Catholics age 70 and over, 85% are white. Of Catholics age 30 and under, about half are Hispanic. Among Catholics, only 40% are age 50 and older — making the Church slightly younger than society at large, in which 41% are 50 and older.

The survey confirmed some things we thought were true. For instance, women are more religious. Pew reports that 5.5% of men say they are atheist or agnostic, more than twice the percentage of women who do.

The survey also taught us some things we didn’t necessarily know. We may have thought, from the large RCIA classes every year, that Catholics include more converts than other religions. Not true. The survey said 89% of Catholics were raised Catholic, which is even higher than the percentage of Jews who were raised Jewish, and about equal to the percentage of Hindus who were raised Hindu.

Popular belief — fueled by erroneous headlines from the Pew study — had suggested that Catholics lose more adherents than other religions. Not true. Only 37% of adults who were raised as Jehovah’s Witnesses still identify themselves as such. And nearly half of kids raised Buddhist leave the faith.

But the survey did tally massive losses to the Catholic Church. Pew noted that, while 31.4% of Americans were raised Catholic, among adults only 23.9% consider themselves still Catholic. In fact, the survey calculated that 10% of Americans are lapsed Catholics.

Godspy.com’s editor Angelo Matera pointed out that this area of the study may misrepresent the true picture a bit.

He cited the headlines that said: “Catholicism has experienced the greatest net losses as a result of affiliation changes.”

But an analysis of Pew by the Center for Applied Research in the Apostolate (CARA) at Georgetown University, paints a different picture — in part by seeing different implications in similar numbers and in part by avoiding erroneous numbers.

CARA compared the Pew results to its own research conducted in 2003.

First, CARA drew attention to the fact that the Pew numbers include a serious methodological flaw. Pew admits that it may have underestimated the Catholic affiliation of Latinos by a gigantic 10 percentage points. That’s a lot of Catholics, and could be the reason CARA reported far fewer Catholics leaving the faith.

Second, CARA made the point that, compared to other religions, Catholics had the third-best retention rate. Only Jews and Mormons are more likely to say they retained the faith they were raised with than Catholics are.

CARA also pointed out that, since the Catholic Church is the largest single Christian “denomination,” the total numbers of Catholics who left the Church looks enormous. But in fact, nearly 7 out of 10 of Catholics who were raised in the faith still claim the faith. That’s still disappointing, but better. (It’s important to note here that, in both studies, all that mattered was what someone said he was. The studies don’t take into account actual Mass attendance.)

Third, CARA’s analysis offered this unexpected tidbit: Most Catholics who left the Church left before 1988. More surprising still: 1 in 4 Catholics who left the Church left before 1962 — before the Second Vatican Council, which has been unfairly blamed for Catholic losses.

Matera did notice one other fact, though. “What CARA didn’t mention in its narrative was a recent trend that leaped off the data table: 23.6% of the lapsed Catholics — almost a fourth — left the Church in the five-year period just prior to the study, 1998-2002.”

He wonders if this “accelerated defection” not only continued, but picked up even more speed, in the years after 2002, the year Church scandals were pounded with relentless ferocity by the press.

At any rate, it’s interesting to look at the numbers to give ourselves a reality check. Some things we thought were bad aren’t so bad after all. And some things that ought to be better are simply atrocious.

Two thoughts. First, one thing the numbers show is that it is ultimately God, not us, who is in charge of the Church. And he keeps his own counsel about his plans.

The numbers that show we have retained many Catholics despite the turbulent times in the Church show that the faith isn’t a thin thread that we are in danger of breaking, but a mighty cord that can withstand the greatest possible strain. It should be no surprise that Vatican II — which we know by faith was inspired by the Holy Spirit — more likely staunched an exodus than precipitated one.

Second, the numbers should remind us that, on this earth, the Church is perpetually in the same state it has always been in. We are weak human beings called to a work all out of proportion to our membership’s size and abilities. Christ is continually saying to us, “Do not be afraid any longer, little flock, for your Father is pleased to give you the Kingdom.”